Ohm's Law review

Ohm's Law review

Physics

​Volts, Amps, and Resistance

​V = I * R

​Voltage = current multiplied by the resistance

​Series:

​R = R1+R2+R3+R4 ...

​Parallel:

​R = 1/R1 + 1/R2 + 1/R3 ...

​

​VIR charts

​-Series VIR chart:

​Do not add currents or Voltage

​Add Resistance

​

​VIR Charts

​Parallel VIR chart:

​Voltage stays the same

​Add Currents

​Resistance does not add up

​VIR Charts

​-Circuits can sometimes contain both series and parallel circuits all in one

​-Rules stay the same but you must treat each circuit as a separate circuit and apply the rules based on that specific circuit.

​-R1 + R3 can be looked at as a series circuit but ...

​- R2, R3, and R4 must be looked at as a parallel circuit

​What is Resistance?

​Resistance is a measure of the opposition to current flow

​-A measure of the difficulty of passing an electric current through a substance or circuit

​--> more resistance = less current flow

​

​What is Current?

​Current is the rate at which electrons flow past a point in a complete electrical circuit.

​-Quantity of electrons flowing past a point in a circuit over a given time

​-Amps

​What is Voltage?

​Voltage is the pressure from an electrical circuit's power source that pushes charged electrons through a conducting wire.

​-negatively charged objects are pulled towards higher voltages, while positively charged objects are pulled towards lower voltages.

​--> It is what makes electric charges move!

​What is Wattage and Power?

​A Watt is the unit of electrical power equal to one amp under the pressur of one volt.

​-Think of Watts as a measure of total electrical flow

​100 W light bulb uses energy at a higher rate than a 60 W light bulb

​The 100 W light bulb needs a bigger energy 'flow' to work.

​Is Power different from Voltage?

​Yes!

​Power is measured in watts (W).

​Equal to the Voltage times the current

​[P=V*I]

​Equal to the squared voltage divided by the resistance

​[P=(V^2)/R]

​Equal to the squared current times the resistance

​[P=(I^2)*R]

​Ohm's law equations

1. ​Resistance:

   1. R=V/I

   2. R=(V^2)/P

   3. R=P/(I^2)

2. ​Amps:

   1. ​I=V/R

   2. ​I=P/V

   3. ​I=SqRt[P/R]

3. ​Voltage:

a. V=I*R

b. ​V=P/I

c. ​V=SqRt[P*R]​

4. Watts:

​ a. P=V*I

​ b. P=(V^2)/R

​ c. P=(I^2)*R

​

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